1. Field of the Invention
The present invention relates to an endoscope shape detecting apparatus for detecting the insertion shape of the insertion portion of an endoscope inserted into a body cavity.
2. Description of the Related Art
Generally, endoscopes are arranged such that a flexible insertion portion is externally inserted into a subject area, i.e., the lumen of the body cavity, thereby allowing the subject area to be observed and necessary treatment to be performed.
However, the lumen of the body cavity is not straight but has many bends, as with the large and small intestines, so a technician cannot readily tell how far the endoscope insertion portion has been inserted, nor what sort of shape the endoscope has.
Accordingly, conventional methods have involved externally irradiating x-rays to the subject area wherein the endoscope insertion portion has been inserted, thereby detecting the insertion position in the lumen in the body cavity, and the shape thereof. However, such x-rays are by no means harmless to the human body. Additionally, the areas where such irradiation can be performed are limited, so such an arrangement is not necessarily preferable as a means for detecting the insertion shape of the endoscope insertion portion.
Accordingly, an apparatus for detecting the insertion shape of endoscopes and catheters using a magnetic field with magnetic field generating means and magnetic field detecting means so as to detect the endoscope insertion shape into the lumen without any negative physiological effects has been proposed, e.g., Japanese Patent Application No. 10-69075 filed by the present Assignee.
However, the above does not provide for detecting the connection state of the magnetic field generating means to the driving means. In the event that the magnetic field generating means is not connected, the magnetic field detecting means picks up background environment noise, at times resulting in an unintended random shape being displayed on the monitor.
In the event that the magnetic field generating means is malfunctioning, the portion corresponding with the malfunctioning portion may be displayed in a deformed manner. In the event that the malfunction involves a short-circuit, excessive current may damage the endoscope shape detecting apparatus itself.
An endoscope shape detecting apparatus or endoscope shape detecting system, wherein an endoscope shape detecting probe comprised of magnetic field generating elements built into the endoscope for detecting the insertion shape is provided within the insertion portion, thereby displaying a three-dimensional image of the insertion shape by a magnetic field detecting device has been proposed in Japanese Unexamined Patent Publication No. 8-107875, etc., for example.
Typically, the entire insertion portion of an endoscope is freely bendable. However, a curving portion is provided on the tip thereof, so repeated usage of the endoscope insertion shape detecting probe in the endoscope necessitates periodic replacement, due to mechanical fatigue. Unfortunately, endoscope shape detecting probes built into the endoscope have not been of an easily-replaceable construction, thus replacement has required a great number of steps.
For example, if the endoscope shape detecting probe to be replaced is forcibly extracted from the endoscope with a force that destroys this endoscope shape detecting probe, the area from which the endoscope shape detecting probe has been removed is narrowed by other built-in members, and an insertion channel for inserting the new endoscope insertion shape detecting probe has not been secured, the new endoscope insertion shape detecting probe to be inserted strikes the other built-in members which essentially prevent the insertion thereof. Accordingly, the device must be disassembled, or subjected to likewise procedures, in order to insert the endoscope insertion shape detecting probe, requiring a great amount of time and much experience to insert the endoscope insertion shape detecting probe into the endoscope.
The endoscope is comprised of a great variety of members over the entire length thereof, such as the curving portion and so forth. Unless an endoscope shape detecting probe closely matching each endoscope configuration is used, correct shape detection is impossible. The selection of the endoscope shape detecting probe for each examination is also a troublesome issue.
With systems wherein the endoscope shape detecting probe is inserted from the endoscope forceps channel in the same manner as treatment equipment used for endoscope inspection, thereby detecting the shape, the endoscope shape detecting probe protrudes from the forceps channel, thus the connector for the endoscope shape detecting probe hangs loosely. The weight of this connector places mechanical stress on the endoscope shape detecting probe, thereby reducing the life expectancy thereof in some cases.
Conventionally, the array intervals of the magnetism generating elements built into the endoscope or the endoscope shape detecting probe were constant.
Endoscopes, flexible endoscopes in particular, are formed with a hard portion at the very tip of the insertion portion, followed by a curving portion and a flexible portion. While the hard portion at the tip never bends, a technician can operate the endoscope such that the curving portion curves into a tight curve. Although the flexible portion does bend, since it is configured in a flexible manner, the flexible portion does not bend into a tight curve, as with the curving portion.
As described above, conventionally, the array intervals of the magnetism generating elements built into the endoscope or the endoscope shape detecting probe are constant. Narrowing the intervals and increasing the number of magnetism generating elements arrayed in the endoscope allows the shape of the curving portion which curves into a tight curve to be detected with high precision, thereby allowing a high-precision image of the shape of the endoscope to be displayed with displaying means, such as a monitor or the like. However, increasing the number of arrayed magnetism generating elements increases costs.
If the intervals are increased and the number of magnetism generating elements arrayed in the endoscope or endoscope shape detecting probe are reduced in order to cut costs, the shape of the curving portion of the endoscope displayed with the display means will exhibit lower precision, different from the true form of the curving portion, as illustrated in dotted lines.
As noted in Japanese Unexamined Patent Publication No. 8-107875, an endoscope shape detecting probe can be inserted into the forceps channel of the endoscope while performing an endoscopic examination, thereby displaying the shape of the endoscope insertion portion on a monitor, thus permitting a technician to make reference to the shape of the endoscope insertion portion displayed on the monitor and readily perform the operations for inserting the endoscope insertion portion deep into the body cavity.
The nature of the endoscope insertion portion itself is determined by the insertion of the endoscope shape detecting probe into the forceps channel of the endoscope. Thus, a technician may not be able to attains a desired stiffness or resilience, or adjust insertion characteristics. Consequently, the technician many not be able to reduce the pain experienced by a patient, or conduct a smooth endoscopic examination.
If an endoscope shape detecting probe is inserted into the forceps channel of the endoscope, the endoscope shape detecting probe hangs freely at the forceps opening of the endoscope. Thus, if the endoscope operating portion is moved or shaken during the examination, stress is placed upon the flexible endoscope shape detecting probe, which may cause deforming or buckling thereof. Consequently, the endoscope shape detecting probe may not be able to be inserted into the forceps channel of the endoscope, or in the worst case, endoscope shape detection may become impossible.
With conventional endoscope arrangements, the magnetic field detecting means is positioned at an absolute spatial position, for easy reference with respect to an examination table upon which the patient lies. The endoscope provided with the magnetic field generating means is inserted into the body of the patient on the bed. The magnetic field generated by the magnetic. geld generating means is detected by the magnetic field detecting means. If the position of the patient changes at the time of inserting the endoscope, the absolute position within the body of the patient changes, making it difficult to ascertain the relationship between the position of the body of the patient and the obtained endoscope shape.
With conventional endoscope shape detection apparatuses, the positions of the magnetic field generating means and the magnetic field detecting means are not close. Accordingly, detection is not always precise, sometimes causing blurring of the endoscope shape image and so forth.
As described in Japanese Unexamined Patent Publication No. 8-107875 for example, a technician had to observe a monitor to know how far the insertion portion had been inserted. In other words, the technician cannot know how far the tip of the insertion portion has advanced into the patient while watching the patient.
Thus, simply displaying the insertion shape of the endoscope still does not allow the technician to readily know how far the endoscope has been advanced into the body cavity. Accordingly, there has been a need to separately provide dedicated source coils for displaying the reference position.
Also, with conventional endoscope shape detecting apparatuses, a monitor for displaying the endoscope shape image generated by the endoscope shape detecting apparatus is provided separately from the monitor for displaying the endoscope image Thus, the technician must perform the inserting operation while observing two monitors, which is problematic.
In recent years, endoscopes which allow observation of an object within the body cavity or treatment or the like as necessary by inserting treatment equipment through a treatment equipment channel of the endoscope without requiring incision, by means of inserting an insertion portion into the body cavity, have come into widespread use. There are various types of such endoscope apparatuses, such as those which have image-taking means, such as a CCD of the like provided on the tip of the insertion portion. Some endoscopes are configured so as to allow separate image-taking means to be attached to the eyepiece of the endoscope, and so forth. These types of endoscopes having image-taking means are arranged so that the image-taking signals from the image-taking means are converted into image signals with a video processor, and displayed on a monitor.
When using such endoscope apparatuses to examiner a body cavity, e.g., the lower digestive organs, insertion proceeds in a smoother manner during the stage of inserting the insertion portion from the anus to the sigmoidal colon if the insertion portion is softer. However, smooth insertion of the insertion portion is hindered in the stage from passing the sigmoidal colon the deeper areas if the insertion portion is too soft. Accordingly, endoscope apparatus have conventionally been used which have stiffness adjusting means for allowing the stiffness or flexibility of the insertion shape detecting means and the insertion portion to be adjusted.
An example of such an endoscope apparatus having stiffness adjusting means is disclosed in Japanese Examined Patent Publication No. 62-7846. The endoscope apparatus in this example has stiffness adjusting means configured of a coil spring provided within the insertion portion in the longitudinal direction. Pressing the coil spring from the rear side forwardly compresses the coil spring, rendering the insertion portion stiffer.
Another arrangement for stiffness adjusting means disclosed in Japanese Examined Patent Publication No.62-7846 involves a coil spring provided within the insertion portion in the longitudinal direction. Pulling a wire passed through this coil spring backwardly pulls the tip of the coil spring fixed to the tip of the wire backwardly, compressing the coil spring so that the insertion portion becomes stiffer.
In using such endoscope apparatuses having stiffness adjusting means, conventional arrangements for the technician to check the stiffness while using the endoscope involved visually checking marks or the like on the stiffness adjustment operating means, such as a knob operated when adjusting stiffness.
Japanese Unexamined Patent Publication No. 8-107875 describes a plurality of magnetic field generating source coils arrayed in the longitudinal direction of the insertion portion at certain intervals, a plurality of sensing coils for detecting the magnetic field generated from the source coils positioned on an examination table upon which the patient lays, and the insertion shape detecting apparatus, which has obtained signals from these sensing coils. The insertion shape detecting apparatus detects the position of each of the source coils, thereby detecting the insertion shape of the insertion portion, and consequently displaying the insertion shape image indicating the insertion shape of the insertion portion on the monitor.
However, the technician must observe the subject image on the monitor connected to the video processor, observe and confirm the insertion state image on the monitor connected to the insertion shape detecting apparatus, and further confirm the stiffness of the insertion portion from the marks on the stiffness adjustment operating means, requiring much eye movement on the part of the technician, causing difficult operability.
With endoscopes having a plurality of source coils for generating a magnetic field for detecting the insertion of the insertion portion, integrally built in at certain intervals, conventional arrangements involved forming a space within the insertion portion of several millimeters in diameter, and disposing the source coils in this space. However, this causes wasted space at the inner diameter of the source coils, resulting in a greater external diameter for the insertion portion. This also exerts occasional pressure on other built-in members, such as the light guide and the like, consequently reducing the durability thereof.
In Japanese Unexamined Patent Publication No. 8-107875, the shape of the insertion portion displayed on the monitor is a 2-dimensional projection of a 3-dimensional form. Thus the accurate length or curvature of the insertion portion may not be ascertainable from the shape displayed on the screen, consequently reducing operability.
A great number of metal members are generally provided near the tip. Sometimes the magnetic field from the source coil is disturbed due to generation of an eddy current. In such cases, the source coil position analyzed by the insertion shape detecting apparatus is erroneous. Accordingly, the insertion shape image is not correctly displayed on the monitor. Also, the curving portion is generally tightly and frequently curved in order to smoothly insert the insertion portion through the body of the subject. Deterioration easily occurs with the members relating to the magnetic field generating elements, such as the source coils positioned within the curving portion, the wiring for providing electricity to the source coils, members for supporting the source coils, and so forth.
Further, the image of the insertion shape displayed on the monitor is a graphic shape approximating the actual shape of the insertion portion. Sometimes precision of the image of the insertion shape deteriorates at positions removed form the positions where the source coils are provided.
Accordingly, it is an object of the present invention to provide an endoscope shape detecting apparatus capable of controlling the monitor display and controlling the driving of the magnetic field generating means, according to the connection state of the magnetic field generating means.
Another object of the present invention is to provide an endoscope wherein replacement of endoscope shape detecting probes can be easily performed.
Another object of the present invention is to provide an endoscope shape detecting apparatus wherein, performing shape detection and endoscopic examination at the same time, the trouble and number of procedures necessary to select an endoscope shape detecting probe which appropriately matches the endoscope selected from a wide variety of endoscopes is reduced, thereby facilitating ease of selecting combinations of matching endoscopes and endoscope shape detecting probes.
Another object of the present invention is to provide an endoscope shape detecting apparatus wherein, when inserting an endoscope shape detecting probe from the forceps channel and detecting the shape, the mechanical stress placed on the endoscope shape detecting probe due to the weight of the connector of the endoscope shape detecting probe is reduced, thereby extending the life of the endoscope shape detecting probe.
Another object of the present invention is to provide an endoscope shape detecting probe or endoscope shape detecting apparatus wherein damage of the probe inserted into the endoscope channel near the endoscope forceps opening is reduced, thereby improving durability, and improving endoscopic examination efficiency.
Another object of the present invention is to provide an endoscope shape detecting apparatus whereby the insertion shape of the endoscope can be detected in an inexpensive manner yet with high precision.
Another object of the present invention is to provide an endoscope shape detecting apparatus capable of accommodating preferences in stiffness/resilience of the endoscope insertion portion and the insertion skills of many technicians, thereby preventing deterioration in the insertability into a body cavity, and consequently improving the efficiency of endoscopic examination.
Another object of the present invention is to provide an endoscope shape detecting apparatus capable of ascertaining with high precision the position of the body of the patient and the insertion shape of the endoscope, regardless of the bodily position of the patient at the point of insertion.
Another object of the present invention is to provide an endoscope shape detecting apparatus whereby a technician can appreciate how far the tip of the insertion portion of the endoscope has been inserted while watching the patient.
Another object of the present invention is to provide an endoscope shape detecting apparatus wherein a reference position can be displayed, without necessitating extra dedicated source coils for display of the reference position.
Another object of the present invention is to provide an endoscope shape detecting apparatus facilitating ease of viewing of an endoscopic image and endoscope shape image, thereby improving the operability of the insertion portion.
Another object of the present invention is to provide an endoscope shape detecting apparatus capable of reducing the amount of eye movement of a technician using an endoscope apparatus having stiffness adjusting means and insertion form detecting means, thereby improving operability.
Another object of the present invention is to provide an endoscope shape detecting apparatus having and endoscope with source coils arrayed within the insertion portion, while preventing increase in the diameter of the insertion portion.
Another object of the present invention is to provide an endoscope shape detecting apparatus whereby the operability of the endoscope system can be improved by quantitatively [knowing] understanding the insertion shape of the insertion portion.
Another object of the present invention is to provide an endoscope shape detecting apparatus having magnetic field generating elements whereby disturbance of magnetic fields due to metal members of the insertion portion can be reduced, and deterioration of the curving portion of the insertion portion can be prevented.
Another object of the present invention is to provide an endoscope shape detecting apparatus whereby the arrayed position of source coils in the insertion portion can be ascertained.
The endoscope shape detecting apparatus according to the present invention comprises:
an endoscope for observing a subject image by inserting an insertion portion into the body of a subject, such as into a body cavity;
a magnetic signal generating means for generating a magnetic field by supplying driving signals; a magnetic field detecting means for detecting the magnetic field generated by the magnetic field generating means; and
a control means, the control means comprising:
a driving means for generating the driving signals;
a computing means for computing the shape of the inserted portion of the endoscope, from relative positional information between the magnetic field generating means and the magnetic field detecting means, based on detection signals detected by the magnetic field detecting means with one or the other of the magnetic field generating means and the magnetic field detecting means;
a display control means for displaying the endoscope shape obtained from the computation results based on the computing means on a display means; and
a connection state detecting means for detecting the connection state of the magnetic field generating means;
wherein the control means controls at least one of the driving means, the computing means, and the display control means, based on the detection results of the connection state;
thereby controlling the display on the monitor and controlling the driving of the magnetic field generating means, according to the connection state of the magnetic field generating means.
Other features and advantages of the present invention will become sufficiently clear from the following description.